Grinding wheel dresser



April 30, 1940. I F. E. BROBERG GRINDING WHEEL DRESSER Filed Aim. 13, 1938 s Sheets-Sheet 1 Z 7werz/iop April 30, 1940. F. E. BROBERG GRINDING WHEEL DRESSER 3 Sheets-Sheet 2 Filed Aug. 13, 1938 I l-i Z7206; r I wC CZ I a April 30, 1940. F. E. BROBERG GRINDING WHEEL DRESSER Filed Aug. 13, 1938 3 Sheets-Sheet 3 Patented Apr. 30, 1 940 GRINDING WHEEL DRESSER -Fred' Edgar Broberg, Racine, Wisqassign or to The Dumore CompanLjRacin'e, Wis. a corporav .5 wheel must be V shaped in cross section. When- My invention relates to improvements in grindtion of Wisconsin Application August 13,

9 Claims.

ing wheel dressers.

Where an emery wheel or other grinding wheel is used to grind threads, the periphery of the anew wheel is purchased, the V shaped angle is only approximately correct and the periphery must be ground with a diamond to make it accurate.

subsequently after a certain amount of use; -To accomplish this grinding with sufficient accu 13 03 the diamond support must be moved in ways or guides arranged at the exact desired angle. v

The main object an improved wheel dresser which may be fitted to any lathe or toa grinding machine. v

, Anotherobject is to provide an improved Wheel f grinder so designed that the work need not be removed from the machine. v

Another object is to provide a device of this I character which, after once being set up in a ceritain lathe, can be removed and when the wheel requires redressing, can be replaced in its exact original location and used-without further adjust- .me

Cert

ain prior devices provide for adjustment of the diamond support to suit the pitch angle only but they cannot be used to dress the grinder for the tooth shape required of a hob or a worm.

A further object of my invention is .to provide. a device which permits templetsto bemade to permit dressing of the grinder for any tooth v shape, including the types just mentioned.

O'therobjects and advantages will be apparent from a consideration-of the following description of a commercial embodiment of the invention.

Fig.

1 is a top plan view of part of a lathewith thepresent commercial form of dresser attachment mounted thereon;

. Fig. Fig.

. Fig.

Fig.

2 is a front elevation of said attachment; 3 isa side elevation thereof; l

l is a side elevation of the grinder;

5 is a front view thereof;

6 is a partial end view;

7 is a front view of a' detail; and

8 is a plan view thereof.

The lathe to which the portable dresser is applied may be any standard lathe. It having the usual ways H, II, and other ways I2, I2, spaced farther apart. Part of the head stock I3 is shown as well as part of the tail stock 14. The part to be ground is mounted on the usual centers and is provided in this instance with a conventional, helical thread I5, as shown inFig. 1. The grinding Also, the periphery must be reground,

of this invention is to provide 1938, SerialfNo. 224,795 (01. 125-11 wheel I16 has its shaft I! mounted in a suitable 3 support orquill I8 with a pulley I9 on the other end, driven by means of a belt from a motor, shown also in Fig. 4. The motor and grinder structure are mounted on the tool pos'tcarriage or cross slide 26 of the lathe.

The dressing device is provided with a suitable base preferably in the form of overlapping plates 2|, 22, which are adjustably held in the desired position by the clamping stud 23, whereby it may slide. onthe ways I I, l I, of any lathe and may be adjusted in accordance with the distance be- "tween said ways. Also, the base is leveledby means of the bolt 24, as shown particularly in Fig. '3. It is clamped to'the lathe bed by the nut 25 which engagesa suitable cross bar in a manner which is well understood, as shown also in Fig. 3. On said base is mounted a supporthaving the general form of an angle iron 26 with a'groove on the rear side which receives a correspondingly shaped portionor slide 21 on the lower end of the vertical support 28, the partsbeing clamped in adjusted position by studs 29. The support 26 may he slid forward or backward in the groove 39 in the part 22, and clamped in place by studs 3L. The upright support 28 carries a vertically" adjustable, non-rotatable disc 32, on which is I mounted a rotatable disc or index plate 33, the graduations thereon being shown in Fig. 1. Said index plate is clamped to the stationary disc by studs or cap screws 34, shown in Figs. 2 and 3. The disc 32 has a pair of diametrically opposite recesses 35 to aid in centering said disc between the lathe centers, as hereinafter explained. The

.rotatable disc 33 carries a horizontal bracket 36 and said disc and. bracket may be swung back or forth through .a substantial angle, i. e. may be set to any helical angle either left or right hand and held in position. w I

The-bracket 36 has a plate 31 secured thereto as by screws 33, said plate being removable and having a notch therein as shown in Fig. 1. Said plate is called a thread angle templet. Said templet and the discs 32, 33, which support it, are held in the desired vertical position by the stud 39.

The templettl carries the diamond supporting member 49 which slides in ways 4 l. The diamond (l2 is held in said supporting member by a set screw 43 and said support may be moved back and forth in its guide ways by hand, to dress the periphery of the grinding wheel Hi to the desired angle. As shown in Fig. 1, the grinding wheel when grinding a helical thread,' does not rotate in, a vertical plane but is inclined some what, as shown, to match the threads I5 on the work piece. The ways 4| have a V shaped arrangement corresponding to the desired angle at the periphery of the grinding wheel. A number of templets are available to provide for any thread angle desired, said templets being interchangeable. The grooves in the templet may also be made so as to make it possible to dress the grinding wheel for worm or hob grinding. In either case the dressing of the wheel is accomplished simply by sliding the diamond support 40 back and forth by hand in one groove and then removing it, and using it again in the other of the two grooves.

The base of the portable dresser is provided with a stop or stops 45, as shown in Figs. 1, 2 and 3. The stop is shown in Fig. l at the rear of the plate 2|, at the right hand side, and. is held in an opening therein by a set screw 46, its projecting screw threaded end being provided with a locking nut 41. A corresponding opening is provided in the left hand side of said plate also for a similar stop. It will be noted that the overlapping base plates 2| and 22 are moved to the right as far as possible in Fig. 1, the position of the base being determined by the stop 45 which engages the carriage 20.

In setting up the dressing device, and assuming that there is no work piece mounted in the lathe, the base is placed on the lathe bed. The stationary disc 32 is placed between the lathe centers or conical spindles, which engage the conical recesses 35 and the base plates 2!, 22 are then adjusted to the size of the lathe bed and are locked in place by the bolt 23. The height of the front part of the base is then adjusted by means of the bolt 24. After these adjustments, the angle support 26 may be moved forwardly to clear the work piece which is to be mounted in the lathe. Assuming that the grinder has already been mounted on the lathe, with the carriage 20 in' approximately the correct position, the base of the dresser must be in a position which will permit the grinding wheel to enter the V-shaped notch in the templet, and this position is attained by the various adjustments permitted by the angle support 26, the fine adjustment being attained by the stop 45 when properly adjusted to engage the carriage 20. The thread angle templet is then adjusted to the desired helical angle, left or right, and assuming that the grinding wheel is a new one requiring dressing, this truing of the grinding surface may now be readily accomplished.

It will be noted that the thread angle templet and associated parts are located between the work and the grinding wheel. Therefore, it is not necessary to remove the Work from the lathe centers during the grinding operation either initially or subsequently. The dressing device may readily be lifted from the lathe bed by loosening the nut 25 and when it is necessary to remount the same on the lathe bed a little later, this may readily be accomplished, and the dresser moved to the right until it engages the carriage 29, at which point the re-grinding operation may take place with assurance that the relative positions of the grinder, the templet and the diamond will be exactly the same as before. Since the carriage 20 travels along the ways of the lathe during the grinding of the thread by the grinding wheel, said carriage may be stopped in any one of a number of diiferent positions, but Whatever its position of rest, the base of the grinder, when the latter is in use, will always be positioned against said carriage and thus maintain the relative position of the device in relation to the feed screw. The stop or stops 45 will also be used when changing from one pitch to another so as to insure that the wheel will be dressed symmetrically with respect to its center line.

It will also be noted that the dressing device need not necessarily be removed from the lathe but if the work piece permits, the grinding wheel may be moved away from the templet to clear the latter and then the templet slid to the left (i. e. toward the head stock) out of the way of the grinder, and the latter moved back to grinding position.

In addition to the obvious advantages of this dresser attachment it will be seen that the indexing discs are located on exact center so that the wheel will be correctly ground, even though it is slightly ofi center. The dressing device is stationary on its base after being adjusted and in being used the grinding wheel is brought up to the dresser unit rather than moving the dressing unit to the grinding wheel, the latter being mounted to utilize a lathe compound permitting this movement. Also, the grinding spindle has a vertical adjustment so as to fit any normal lathe. The design of the dresser parts is such that there is no chance of errors from adjustments. The dresser base and the grinder base are independent, so that the former may be made to'fit any lathe. I

,The dresser can be fitted to any lathe or to certain types of grinding machines merely by changing the effective length of the overlapping base plates or by replacing one of them with a longer plate where the limits of the base shown in the drawings, are exceeded.

The grinder, as previously stated, is supported on the carriage 29, by a supporting plate (Fig. 4)

forming part of an angle plate, the upper flange of which is indicated at 48. The vertical plate 48 has mounted behind it additional adjustable plates 49 and 50, as shown also in Figs. 5 and 6. The plate 50 carries a boss 5| which supports the bracket 52 on which the motor 53 is mounted. The purpose of said adjustable plates is to permit the motor shaft to be swung about a certain axis of rotation, to tilt the grinding wheel or disc out of a vertical plane into some predetermined inclined plane, as hereinafter described. The motor drives the pulley l9 by a belt 54.

On the rear of the supporting plate 48 is an arc shaped groove 55 which receives a correspondingly curved rib 56 on the front of the plate 49, which is shown more fully in Figs. '7 and 8. The opposite end of said plate is curved at 51, and has screw threaded openings 58, 59 therein to receive studs 69, 6 I, slidable in the curved slots in plate 48, shown in Fig. 5. By this means the plate 49 may be clamped in any desired position of angular adjustment with respect to a horizontal axis passing through the edge of the grinder and intersecting the axis of the shaft on which it is mounted.

Said plate 49 has two additional screw threaded openings 52, 63 therein to receive the studs 64, 65, which permit vertical adjustment of the plate 50 to therear of the plate 49. Said studs pass through vertical slots 66 in the rear plate 50. Said rear plate is guided in its up and down movement by a slot in the rear face of the plate 49, which slot receives a rib 68 on the rear plate 50, as shown in Fig. 1.

The curved end of the front plate 48 has graduations 59 thereon representing circumferential degrees, to aid in adjusting the plate 49 rotatively.

Such rotation, it will be noted, also swings the entire motor structure and its supporting parts,

that to which the dressing device is set. For

this purpose the graduations ,69 in Fig. 6 correspond to those shown on the dressing device in Fig. 1.

In setting up the grinder the parts 48 and 49 are first locked together in the zero position, as in Fig. 6. The part 48 is then fastened to the lathe compound with the usualT bolt and nut.

The frame of the grinder is then mounted on the boss 5| and secured in position. The shaft I1 of the grinding wheel is then mounted between the lathe centers to hold it in the proper position while the vertical adjustment is accomplished by means of the cap screws 64, 65. .If the lathe is of such a size that the slots 66 are too short to permit the desired adjustment, parallel bars are inserted between the lathe compound and the base 41, to give the rough adjustment, the said slots and cap screws providing for the finer adjustment. The grinder is then removed from the centers and backed up to be adjusted to whatever helical angle is desired, by loosening. the cap screws Bil, 6|, swinging the grinder structure and its supporting parts to the desired angle and then looking the parts in position. It will be noted that while this helical angle adjustment is being made, the plates 49, 50 and the parts supported thereby are held by the curved rib 56 which engages its slot 55 in the part 48.

While I have shown and described one embodiment of my invention, it is to be understood it is capable of many modifications. Changes, therefore, in construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended means for adjusting one side of said base vertically with respect to said ways.

3. The combination with a lathe having a tool A post carriage, of a grinding wheel mounted on said carriage, a wheel dresser. comprising a base having two relatively adjustable members arranged to slide on the ways of said lathe, means for securing said base to said ways, an upright member slidably mounted on said base to permit adjustment back and forth thereon, a fixed plate on said upright member, an index plate rotatably secured to said fixed plate and a templet on said index plate having V grooves therein to support and guide a diamond holder.

4. A grinding wheel dresser asin claim-3, with means for adjusting said upright member With respect to said two-part base, in a direction parallel to the ways of the lathe.

5. A portable dresser comprising a base adjustable along the ways of a lathe, a vertical standardadjustable on said base both longitudinally and transversely,- a thread angle templet vertically adjustable on said standard and an adjustable stop onsaid base to engage the lathe carriage and insure the same location of said base with respect to said carriage and the feed screw therefor when said dresser is removed from said lathe and subsequently restored thereon.

6. A portable dresser comprising a base adjustable to the ways of lathes of different sizes,.a vertical standard adjustable thereon both longitudinally and transversely, avertical plate adjustable in ways on said standard, a second plate rotatably mounted on said first plate and a templet support on said second plate.

'7. In a grinding wheel dresser, a base, a vertical member thereon having a horizontal groove therein, a vertical standard having a rib thereon fitting said groove and means for clamping said standard to said member in adjusted position horizontally, a plate having an extension slidable vertically on said standard, means for clamping the same at the desired height, said plate having recesses on opposite sides to permit centering in aglathe, a second plate rotatably mounted on said first plate in contact therewith, a stud and slot connection to adjust said second plate to the desired helical angle of the thread to be ground, and a third plate having V grooves therein removably secured to said second plate.

8. A grinding wheel dresser as in claim '7. with the addition of a diamondholder slidable in said grooves. Y

9. A portable dresser comprising a base slidably mounted on the ways of a lathe, a vertical standard adjustable both longitudinally and transversely on said .base, a thread angle templet vertically adjustable on said standard and a stop on said base to engage the lathe carriage and insure the same location, of said base with respect to said carriage and the feed screw therefor when said dresser is removed from said lathe and subsequently restored thereon, regardless of 'the position in which said carriage may come to 

